Ten minutes a month keeps your AC running
In Central Texas, your air conditioner may run from April through October with very few breaks. That is a lot of work for one system, and it usually quits on the hottest day of the year.
Most AC breakdowns we see start with something small: a dirty air filter, a clogged drain line, or a dead thermostat battery. A simple monthly routine prevents most of them. And when something does go wrong, a few quick checks can often get you cool again before you ever need to submit a work order.
This guide has two parts: what to do every month, and what to check when your AC stops cooling.
Safety first: Never open the electrical panels on your indoor or outdoor unit, and never try to repair wiring or refrigerant lines. If you smell burning or see smoke, turn the system off at the thermostat and submit an urgent work order right away. If you smell gas or see fire, leave the home and call 911.
Part 1: Your monthly maintenance routine
Pick one day each month, such as the 1st or the day you pay rent, and set a phone reminder. These four steps take about 10 minutes.
1. Change or clean the air filter
A clogged air filter is the most common cause of poor cooling we see. When the filter is packed with dust, pet hair, and pollen, air cannot move through your system. The AC works harder, cools less, and raises your electric bill. Over time, low airflow can freeze the indoor coil and shut the system down.
Why monthly? Many filter packages say "up to 90 days," but that assumes mild weather and light use. In Central Texas, systems run almost nonstop for half the year, and homes with pets or nearby construction clog filters even faster.
- Turn the system off at the thermostat.
- Find the filter. It is usually behind a return air grille in a wall or ceiling, or in a slot at the indoor unit.
- Note the size printed on the edge of the old filter (for example, 20x25x1) and buy the same size.
- Slide the new filter in with the arrow pointing toward the unit, the direction air flows.
- Write the date on the edge of the new filter.
Basic pleated filters work well for most homes; you do not need the most expensive option.
Have a reusable filter? Some homes have washable filters instead of disposable ones. This includes every window unit and some central AC systems. A reusable filter usually has a plastic or metal frame with no cardboard, and it may say "washable" or "permanent" on it. Clean it monthly, or every 2 weeks for window units during summer.
- Turn the system off at the thermostat. For a window unit, turn it off and unplug it.
- Remove the filter. On a window unit, it is usually behind the front grille or a pull-out panel. On a central system, it is behind the return air grille or in the slot at the indoor unit.
- Vacuum off loose dust with a brush attachment.
- Rinse it with lukewarm water, spraying from the clean side so dust is pushed out the way it came in. For a greasy or very dirty filter, use a little mild dish soap. Do not use harsh chemicals or a dishwasher.
- Let it air dry completely before reinstalling. A damp filter can grow mold and damage the unit.
- Reinstall it with the airflow arrow pointing toward the unit, if it has one.
Never run the unit without the filter in place, even while the filter is drying. Cleaning it in the morning gives it time to dry before evening. If a reusable filter is torn, bent, or will not come clean, submit a work order.
2. Flush the AC drain line with vinegar
Your AC also pulls moisture out of the air, often several gallons a day in a humid Texas summer. That water drains through a small PVC pipe called the condensate drain line. Algae and slime build up inside it over time, and a clogged line can shut down your AC or cause a leak. A monthly vinegar flush keeps it clear.
What you need: 1 cup of plain distilled white vinegar and a small funnel (optional).
- Turn the AC off at the thermostat.
- Find the access port near the indoor unit (in a closet, garage, or attic). It is a short PVC pipe coming off the drain line, often shaped like a "T" with a removable cap.
- Remove the cap and slowly pour in 1 cup of white vinegar.
- Replace the cap and wait 30 minutes.
- Turn the AC back on. Normal condensation will carry the vinegar through the line.
Do not mix cleaners. Never pour bleach into a line that has vinegar in it, or the other way around. Together they create a harmful gas. Vinegar alone is all you need. If you cannot find the access port, submit a work order and we will assist you in finding it.
3. Clear around the outdoor unit
Keep at least 2 feet clear on all sides. Trim back grass and weeds, and remove leaves, toys, and stored items. With the AC running, make sure the fan on top is spinning.
4. Check your vents
Keep supply and return air vents open and unblocked by furniture, rugs, or curtains. Closing vents in unused rooms does not save energy; it strains the system.
Once a year: replace the thermostat batteries
Most thermostats use AA or AAA batteries. Replace them every year, even if they still work. Many residents do it when they change the clocks in the fall.
Monthly checklist
- Replace or clean (if reusable) the air filter
- Pour 1 cup of white vinegar into the drain line access port
- Clear grass, leaves, and clutter from around the outdoor unit
- Make sure vents are open and unblocked
- Once a year: replace the thermostat batteries
Part 2: Troubleshooting when your AC stops cooling
Work through these checks in order. Most problems are solved in the first three.
1. Check the thermostat
- Look at the screen. A blank or dim display, or a low-battery icon, usually means dead batteries. Replace them.
- Check the mode. Make sure it is set to Cool (or Heat in winter), not Off or Fan.
- Check the setting. Set it at least 3 degrees below the current room temperature.
- Wait 5 minutes. Many systems have a built-in delay to protect the compressor after a change.
2. Check the breaker
If the thermostat has power but nothing runs, look in your electrical panel for a tripped breaker labeled AC, HVAC, furnace, or air handler. Flip it fully off, then back on, once. If it trips again, leave it off and submit an urgent work order.
3. Check the air filter
If it has been more than a month, or the filter looks gray or dark, replace it now. A badly clogged filter alone can stop your home from cooling.
4. Check the drain line
Most systems have a safety float switch that shuts the AC off when the drain line backs up, to prevent a flood. The thermostat may still show power, but the system will not cool. Signs of a clog include:
- Water standing in the drain pan under the indoor unit
- Water on the floor around the unit, or a wet spot on a ceiling below an attic unit
- No water dripping from the outside end of the drain pipe on a hot day
- A musty smell, or the AC turning on and off repeatedly
What you can safely do:
- Turn the system off at the thermostat.
- Soak up any standing water in the pan and on other surfaces (floors, closets, etc.) with towels or a wet/dry vacuum.
- Find the outside end of the drain line, usually a small PVC pipe near the outdoor unit or foundation. Hold a wet/dry vacuum hose tightly over the end and run it for 1 to 2 minutes to pull out the clog.
- Do the vinegar flush from Part 1, wait 30 minutes, then turn the AC back on.
If water keeps backing up, the AC will not restart, or water has reached the ceiling or floors, stop and submit a work order.
5. Look for ice
Frost or ice on the copper lines or indoor coil means the system has frozen, usually from a dirty filter or low airflow. Turn the thermostat to Off and the fan to On for 2 to 4 hours to thaw it, then replace the filter and try again. If it freezes a second time, submit a work order.
6. Know what "normal" looks like on hot afternoons
Close blinds on sun-facing windows and avoid running the oven or dryer during the hottest part of the day. On a 100-degree afternoon, a system that runs nonstop but keeps the house about 20 degrees cooler than outside is often working normally.
Still not working? Submit a work order
Once you have checked the thermostat, breaker, filter, and drain line, it is time to let us take over. Log in to your tenant portal and submit a work order. Submitting through the portal gets your request to our maintenance team right away and lets you track its status.
To help us fix it faster, include:
- What is happening (not cooling, not turning on, leaking, making noise) and when it started
- What you already checked from this guide
- A photo of the thermostat screen and the indoor unit, plus any water or ice
- Whether we have permission to enter if you are not home, and any pets in the home
Mark your work order urgent if you notice:
- A burning smell, smoke, or sparks from any part of the system
- Water leaking through a ceiling or soaking floors or walls
- A breaker that trips again after one reset
- Loud grinding, banging, or screeching from the indoor or outdoor unit
- No cooling during extreme heat, especially with infants, older adults, or anyone with a medical condition in the home
If you smell gas or see fire, leave the home immediately and call 911 from outside. Submit a work order once you are safe.
A note on responsibilities: Your lease explains which maintenance items are yours, such as replacing air filters and thermostat batteries and keeping drain lines clear. A service visit caused by a clogged drain line, a skipped filter change, or a dead battery will incur a bill to the resident, so the monthly routine above can save you money as well as keep you comfortable.
Frequently asked questions
What AC maintenance should renters do every month? Replace the air filter, pour 1 cup of white vinegar into the condensate drain line, clear around the outdoor unit, and make sure vents are open. It takes about 10 minutes.
How often should I change my air filter in Texas? Every month as stated in the lease. Long cooling seasons, dust, pollen, and pets clog filters faster than the 90 days printed on many packages.
How much vinegar do I pour in the AC drain line? About 1 cup of distilled white vinegar, once a month, with the system off. Let it sit for 30 minutes before turning the AC back on.
Why did my AC shut off by itself? A clogged drain line often triggers a safety float switch that turns the AC off to prevent a leak. Clearing the line and flushing it with vinegar often fixes it.
Why is my AC running but not cooling? The most common causes are a dirty filter, a frozen coil, or the outdoor unit not running because of a tripped breaker. Check those first, then submit a work order in the tenant portal.
My thermostat screen is blank. What should I do? Replace the batteries first. If it stays blank, check the HVAC breaker, then submit a work order.
Resolute Leasing manages rental homes across Killeen, Harker Heights, Copperas Cove, Belton, Temple, and the rest of Central Texas. Look for more tips in our Tenant Maintenance Tips and Troubleshooting series.
